100 THE CATTLE OF GREAT BEITAIN. 



it is casein combined with the fat, and a portion of the mineral 

 matter; whilst in the resulting fluid, known as whey, remains 

 the milk sugar, the albumen, small portions of the fat and 

 casein, and most of the mineral matter. The division of the 

 curd from the whey is brought about by the use of rennet, a 

 liquid prepared from the fourth stomach of the sucking calf, 

 which is especially arranged by nature for digesting curd. The 

 value of rennet is not in its mere capacity to curdle milk, for 

 this phenomenon will result from the use of almost any power- 

 ful acid. It is in the fact that it is a digestive agent converting 

 the raw curd into a mellow and deliciously flavoured cheese. 

 The importance of the purity of rennet cannot therefore be too 

 highly estimated. The Cheddar process, which is the safest and 

 most largely followed, is thus described by Dr. Voelcker : — 

 " Immediately after morning milking, the evening and morning 

 milk is put into a Cockey's tin tub, having a jacketed bottom 

 for the admission of steam or cold water. The temperature of 

 the whole is slowly raised to 80°, by admitting steam into the 

 jacketed bottom. The rennet is now introduced, the tub covered 

 with a cloth, and left for an hour. If annatto for colouring 

 is used, it must be added before the rennet. Grood rennet 

 should properly coagulate milk at 80° in from three-quarters 

 of an hour to an hour. If the milk fails to be coagulated 

 within the hour, the curd produced will be tender, and not 

 easily separated from the whey without loss of butter ; whereas, 

 on the other hand, if the curd is separated in twenty to twenty- 

 five minutes, the cheese is usually sour or hard. Great care 

 should be exercised, in preparing the rennet so as to ensure 

 uniform strength. At the end of the hour the curd should 

 be partially broken, and allowed to subside for half an hour, 

 after which the temperature is gradually raised to 108° Fahren- 

 heit, the curd and whey meanwhile being gently stirred with a 

 wire breaker, so that the heat is uniformly distributed and 

 the curd minutely broken. The heat is maintained at 108° for 

 an hour, during which time the stirring is continued. The 

 curd, now broken into pieces the size of a pea, is left for 

 half an hour to settle ; at the end of this time the whey is 

 drawn off by opening a spigot near the bottom of the tub. 

 As the curd should be quite tough, no pressure is at first 



